In a nutshell, this means you are free to use the software and its source code in your projects. If you use (parts of) the source code in another software project, you are required to add attribution to the author. You are encouraged to share the your source code in a similar fashion, but it is not a requirement.

QTVR

QTVR, short for Quicktime Virtual Reality, is a technology embedded in Apple's Quicktime media framework. As a result, the Quicktime .mov file format was the original container for interactive panoramas. Panoramic images are encoded into chunks as if they were a video stream, and special information about the view parameters (initial pan/tilt/zoom, limits for each parameter, etc) is added to special atoms in the video description.

Since its inception in 1996, Apple seems to have lost their initial interest in the technology, and support - let alone new developments - have been waning. These days Flash-based viewers have taken over the prevalent role of displaying interactive panoramas that Quicktime once had. Even so, the Quicktime file format can still be an interesting container for interactive panoramas.

There is a huge wealth of existing content in the QTVR container. But there's also a matter of convenience; almost all stitching applications support the QTVR format for export, and the single binary package for the image and all its metadata is convenient for uploading to the web.